1. Field of the Invention
The present invention relates to the plating of electrosurgical instruments, and, more particularly, to the plating of the steel blade of an electrosurgical instrument with an intermediate metal layer to enhance electrical conductivity.
2. Description of Related Art
Electrosurgical knives or blades currently utilized by surgeons essentially comprise a surgical steel cutting tool, such as a scalpel, and a source of radiofrequency electrical energy for application to the cutting tool. When used in surgery, the surgeon controls the application of radio-frequency electrical energy to the blade to generate heat and cause hemostasis as tissue is cut. In this manner, bleeding is minimized during surgery.
While proven effective for controlling bleeding during surgery, electrosurgical knives are rendered less efficient by the sticking of tissue to the blade such that replacement of the blade is ultimately necessary. A common approach in addressing this problem has been to coat the blade with some type of non-stick material to which the cauterized tissue is less likely to adhere. However, the non-stick coating must not prevent the passage of sufficient electrical current from the blade to the tissue to achieve hemostasis.
Methods currently employed to achieve reduced sticking to tissue in electrically-conductive electrosurgical blades are directed to the configuration of the non-stick coating. For example, U.S. Pat. No. 4,785,807 discloses an electrosurgical knife in which the thickness of the non-stick coating is limited to about 3 mils so that the knife remains conductive. While the electrical conductivity of a steel blade having a thin non-stick coating is undoubtedly improved over one having a thicker coating, the electrical conductivity remains impeded to a degree. Other methods involve providing small, interspersed conductive openings in a non-stick coating to expose the metallic knife blade to the tissue and ensure the passage of electrical current from the blade to the tissue. However, these openings typically become coated with charred tissue such that the knives are rendered nonconductive and unusable.
It is therefore desired to provide an electrosurgical knife having both a reduction in sticking and an optimal electrical conductivity. Further, the knife must be readily cleaned and easy to manufacture.